The market for wireless base station antennas is highly price and performance competitive. For this reason, it is advantageous to develop antennas having functions that are suitable for use as wireless base station antennas, and that exhibit desirable initial and lifetime cost characteristics. At the same time, it is also desirable to outfit the antennas with a significant range of operational flexibility, so that a standard antenna design may be used for a wide range of potential antenna sites and feature preferences. Meeting these often conflicting design objectives is a continuing challenge for the designers of wireless base station antennas.
In particular, adjustable downtilt and sidelobe minimization are desirable characteristics for a wireless base station antenna. Conventional methods for implementing adjustable downtilt have included mechanical downtilt systems that rely on manual or motorized bracket adjustment. Alternatively, conventional electrical downtilt systems typically rely on multiple beam steering phase shifters. These techniques are relatively expensive to implement. In addition, sidelobe minimization has conventionally been accomplished through relatively complicated antenna element spacing, power distribution, and phase control schemes. These techniques are also relatively expensive to implement.
Accordingly, there is an ongoing need for more cost effective systems for implementing beam tilt and sidelobe minimization for wireless base station antennas.